rHuIL-11 is fully biologically active when compared to standard. The ED50 as determined by the dose-dependent stimulation of the proliferation of murine 7TD1 was found to be < 10ng/ml, corresponding to a Specific Activity of 1x10e5 IU/mg.

AA Seqeunce

The sequence of the first five N-terminal amino acids was determined and was found to be Gly-Pro-Pro-Pro-Gly. N-terminal methionine has been completely removed enzymatically.

Dimers and Aggregates

1% as determined by silver-stained SDS-PAGE gel analysis.

Protein Content

Protein quantitation was carried out by two independent methods:

1. UV spectroscopy at 280nm using the absorbency value of 0.95 as the extinction coefficient for a 0.1% (1mg/ml) solution. This value is calculated by the PC GENE computer analysis program of protein sequences (IntelliGenetics).

2. Analysis by RP-HPLC, using a calibrated solution of IL-11 as a Reference Standard.

Storage and Stability

Lyophilized powder may be stored at 4°C for short-term only. Reconstitute to nominal volume by adding sterile dH2O and store at -20°C. Reconstituted product is stable for 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.